This invention relates to a process for the production of hydrocarbons having two or more carbon atoms by the oxidative coupling of methane.
While methane is abundantly obtained from natural gas, its utility is now limited only to a few applications. Because of possible exhaustion of petroleum in the not very distant future, the use of methane as a raw material for chemical products is highly desired.
A method is known to obtain C.sub.2 or higher hydrocarbons such as ethane and ethylene by contacting a mixed gas containing methane and oxygen with a catalyst such as lithium-magnesium oxide (J. Am. Chem. Soc., 1985, 5062 (1985)), a rare earth metal oxide (Japanese Tokyo Kokai 61-165340), a rare earth metal carbonate (Japanese Tokyo Kokai 1-143838), an alkaline earth metal oxide (Chem. Lett., 1985, 49 (1985)) and perovskite compounds, e.g. A103 (J. Am. Chem. Soc., Chem. Commun. 49, (1986)), BaCeO.sub.3 (Chem. Lett., 1987, 1985) and BaPb.sub.1-x BiO.sub.3 (J. Mater. Science Lett., 8, 17 (1989). Because the known method is carried out in the presence of molecular oxygen, by-products such as carbon monoxide or carbon dioxide are apt to be yielded so that the selectivity to C.sub.2 or higher hydrocarbons is lowered. Further, even if the production of such by-products can be suppressed and the C.sub.2 or higher hydrocarbons can be produced with both high yield and selectivity, it is necessary to concentrate the C.sub.2 or higher hydrocarbon product because the concentration of methane in the feed gas is not high.